Process optimization and kinetics for leaching of cerium, lanthanum and neodymium elements from iron ore waste's apatite by nitric acid

Ferdowsi, A ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1016/S1003-6326(17)60048-7
  3. Publisher: Nonferrous Metals Society of China , 2017
  4. Abstract:
  5. The leaching of rare earth elements (REEs) including cerium, lanthanum and neodymium from apatite concentrate obtained from iron ore wastes by nitric acid was studied. The effects of nitric acid concentration, solid to liquid ratio and leaching time on the recoveries of Ce, La and Nd were investigated using response surface methodology. The results showed that the acid concentration and solid to liquid ratio have significant effect on the leaching recoveries while the time has a little effect. The maximum REE leaching recoveries of 66.1%, 56.8% and 51.7% for Ce, La and Nd, respectively were achieved at the optimum leaching condition with 18% nitric acid concentration, 0.06 solid to liquid ratio and 38 min leaching time. The kinetics of cerium leaching was investigated using shrinking core model. It was observed that the leaching is composed of two stages. In the first stage a sharp increase in cerium leaching recovery was observed and at the longer time the leaching became slower. It was found that in the first stage the diffusion of reactants from ash layer is the rate controlling mechanism with an apparent activation energy of 6.54 kJ/mol, while in the second stage the mass transfer in the solution is the controlling mechanism. © 2017 The Nonferrous Metals Society of China
  6. Keywords:
  7. Shrinking core model ; Activation energy ; Apatite ; Cerium ; Iron ores ; Lanthanum ; Lanthanum oxides ; Liquids ; Mass transfer ; Neodymium ; Nitric acid ; Optimization ; Phosphate minerals ; Rare earth elements ; Rare earths ; Recovery ; Shrinkage ; Surface properties ; Apparent activation energy ; Nitric acid concentration ; Optimum leaching conditions ; Rare earth elements (REEs) ; Rate-controlling mechanism ; Response surface methodology ; Solid-to-liquid ratio ; Leaching
  8. Source: Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 27, Issue 2 , 2017 , Pages 420-428 ; 10036326 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S1003632617600487